Filter, strainer, and the like



June 22, 1937. F. 'Q L, CHORLTN 2,084,433

FILTER, STRAINER, AND THE ,LIKE

Filed Oct. 12, 1935 M /ff/f wf Y@ Patented June 22, 1937 UNITED STATESPATENT OFFICE pplication October 12, 1935, Serial No. 44,794

' In Great Britain October 27, 1934 6 Claims. (Q1. 210-169) 'Ihisinvention relates to filters or strainers, and more particularly tolters or strainers for separating very fine solid particles from oil.

I have illustrated my invention in the accompanying drawing, in which:-

Figs. 1 and 2 show a cage construction suitable for use in that type oflter in which the cage on which the wire is wound is fixed in locatingseatings in the filter casing so that the filteringl medium isinterposed between the inlet and the outlet;

Fig. 1 being a sectional elevation on the line I-I of Fig. 2; and

Fig. 2 a plan, the left-hand half showing the casing and cover in medialsection, and the righthand half showing the casing and cover in medialsection and also showing the cage in section on the line II-,II of Fig.1.

Fig. 3 is an elevation of a rotatable vfiltering unit showing a methodof cleaning.

Figs. 4 to 11 illustrate cross-sections of wire which may be employed incarrying out the invention.

Fig. 12 illustrates to a considerable enlarged scale a fragmentarysection on the plane XII- XIIof Fig. 1 as shown to a smaller scale at :cof Fig. 2, and

Figs. 13 and 14 are views similar to Fig. 12 and show grooves modifiedto suit wires of semicircular and trapezoidal shape. Y

Referring first toFigs. 1 and 2;-

A is a cage or former comprising a cylindrical portion al havingexternally projecting longitudinally disposed ribs a2, formingwater-ways a3; at opposite ends the ribs a2 are connected by flanges a4which fit with suitable jointing, in seatings bi and b2 of the filtercasing B. In the outer faces a6 of theribs a2 which are of cylindricalconguration, grooves are cut which form interrupted portions of ahelical groove running from end to end oi.' the cage, the pitch of whichis slightly greater than the maximum transverse dimensions oi' the wireemployed; if a wire of triangular cross-section (as shown in Fig. 4) isemployed, a V-shaped groove (as shown in Fig. 12) would be cut, thedepth of the groove being less than the distance from the apex of thetriangle (Fig. 4) to the base thereof; a portion of the wire winding isshown at C; the ends oi' the wire are suitably secured and the cage isretained in any suitable manner in its seatings bl and b2 across thewater-way of the tllter. the arrangement being such that liquid can passfrom the inlet vpart b3 of the lter to the outlet part b5 through thefiltering medium only; in Figs.

1 and 2 the ow of the water to be illtered is inwardlyv through thehelical interstices between scribed except that the cake or former A' isrotatably mounted in the casing B'; the former A is provided withinterior teeth a2il with which a wheel G engages; the wheel G is mountedon a spindle gl mounted in the casing A, and is adapted to be rotated byany suitable means, for example by an external handle on the spindle glor by power, and a brushH is mounted onxa spindle hl in the casing incontact with the ltering medium, whereby when the cage A' is rotated theltering medium is cleansed from dirt or other matter adhering to theoutside.

The filtering medium formed of wires of sections shown in Figs. 4 to 11may be employed, the shape o f the helical groove being modified asshown for example in Figs. 12 and 13.

Of the sections of wire given by way of example in Figs. 4 to 11, thewires shown in Figs, 4, 5, 7, 8

and 11 are suitable vfor those cases in which the grooves in the ribs onwhich the wires are' wound are adapted to take the apex or narrowestpart cl of the section, as in Figs. 12, 13 and 14. e

In the cases of wires of the sections shown in Figs. 4, 5 and 8 thesurface presented to the ow of liquid to be i'lltered is practically theplain cylindrical surface formed yby the-aligning faces c2 of the baseofthe section; in Figs. '7 and 11 the surfaces on each side of theentrance to the helical passage-Way` farm a reentrant angle which isfound to be of advantage in some cases.

The sections shown in Figs. 6, 9 and 10are suitable for use when thegrooves in the ribs' ished; similarly the wire of Fig. 10 could be woundin helical grooves of triangular crosssection' as in Fig. 12, the anglebetween the sides of the grooves being an obtuse angle as at c4 Fig. 12.

The bases cl (Figs. 6. 9 and 10) are in the construction last describedon the entrance side to'the helical groove, the flow in this case beingoutwardly through the wire-wound filtering medium; the radius ofcurvature of the sides of the base cl of Figs. 6 and 9 is therefore madecomparatively great, and the angle between the two sides of the base c4in Flg.\10 is made very obtuse, in order to prevent any wedging actiontak- 10 ing place which would tend to clog the entrance to the helicalpassage-ways.

The configuration of the unit is above referred to as approximatelycylindrical but obviously the 4wire-wound helix isnot truly cylindricalbut pol'5 lygonal, and where desired the body part al of the cage A maybe made polygonal.

Having now fully described my invention, what I claim and desire tosecure by Letters Patent isz- 1. In filtering apparatus in combination;afllter casing having inlet and outlet openings; a cage located withinthe casing and having peripherally situated, circumferentially spaced,longitudinally disposed upstanding members constituting a polygonalformer to support a filtering element comprising a wire helix woundthereon with a space between successive convolutions; jointing means onthe casing and on the cage which when jointed connect the enclosed spaceoutside the helix to one of the said casing openings and the enclosedspace within the helix to the other said opening; and a filteringelement consisting of a wire helix wound on said cage members with aspace between its successive convolutions, the normal transversecross-section of the wire of which the helix is wound being a segment ofa circle, the helix being wound with a part oi' the circular peripheryof the wire on and supported by the longitudinal members of the former,and 40 with the side of the wire Vwhich in transverse section is astraight line rdisposed in a surfaceof revolution, the generatrix ofwhich is a line, and the axis of which is the axis of the helix, thepitch of the helix being slightly greater; than the width of the saidside.

2. In filtering apparatus in combination;-a cage comprising a hollowcylindrical portion with end flanges, the outer portion of the cylinderhaving a series of circumferentially spaced ridges forming a series ofshallow troughs bounded by the flanges and the ridges, passage-waysbeing provided through the flanges, one at each end of each trough; acylindrical casing open at one end to admit the cage and having anopening through the opposite end and an opening through the side of thecasing, one of said openings forming the inlet and the other the outletfor the fluid to be filtered; a seating in the said casing locatedbetween the two said openings to make joint with the inner flange of thecage when the latter is inserted in the casing; a seating at the openend of the casing to make joint with the other flange of the insertedcage; and a cover to close the open end of the casing, the inner face ofsaid cover being some distance axially away from the adjacent flange ofthe cage; and a filtering medium consisting of a wire helix wound onsaid cage ridgeswith a space between its successive convolutions, thenormal transverse cross-section of the wire of which the helix is woundbeing a figurev having one side which is approximately a straight lineof length greater than any other transverse dimension of the figureparallelto said-line, the two sides of the figure adjacent the saidstraight line side converging in a direction away from the said straightline, the helix being wound with the side of the wire corresponding withthe said straight line substantially forming a plain cylindricalsurface. A

3. A filter constructed in accordance with claim 2, and in which theinlet for the flow of fluid to be filtered is the side opening of thecasing, in which the wire forming the helix is of triangularcross-sectiony wound on the cage so that the apex is supported by theridges of the cage and the side of the wire opposite the apex is woundto form a plain cylindrical surface intersected by a helical slot.

4. A filter constructed in accordance Awith claim 2, and in which theinlet for the flow of fluid to be filtered is at the end of the casingin which the wire forming the helix is of triangular cross-section woundon the cage so that one side of the wire is supported by the ridges, thehelix having a plain cylindrical interior traversed by a helical slot.

5. A filter constructed in accordange with claim 2, in which the wireforming the filtering medium is of trapezoidal cross-section.

6. A filter constructed in accordance with claim 2, in which the wireforming the filtering medium is of semi-'circular cross-section.

FRANK O. L. CHORLTON.

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